Frame done, finally...
OK. I figured out a frame that works for my preferences....
I created a frame for the lower compartment, that makes the zipper track more vertical so that it's easier to remove and replace discs. The frame is like an upside down U. I can fit 15 nicely with some room to pull discs out easily. I can get 16 in there, but then it's a tight fit and I have to pry the discs on the sides out with more effort. Click the photos for larger views.
Pic 1 shows the compartment with 15 discs.
Pic 2 shows the empty compartment
Pic 3 shows the roof of the lower compartment with the top part of the frame against the divider between lower and upper compartments.